   (reset! max-undos n))
 
 ;;
-(def ^:private undo-list (atom []))   ;; a list of history states
-(def ^:private redo-list (atom []))   ;; a list of future states, caused by undoing
+(def ^:private undo-list (reagent/atom []))   ;; a list of history states
+(def ^:private redo-list (reagent/atom []))   ;; a list of future states, caused by undoing
 
 
 (defn clear-history!

  (:require
    [reagent.core      :as     reagent]
    [re-frame.db       :refer  [app-db]]
    [re-frame.handlers :as     handlers ]
    [re-frame.subs     :as     subs ]))



                           @max-undos
                           (conj @undo-list @app-db)))))

(defn undos?
  []
  (>= (count @undo-list) 1))

(defn redos?
  []
  (> (count @redo-list) 0))


;; -- subscriptions  -----------------------------------------------------------------------------
